Cordless window shade

ABSTRACT

A cordless widow shade includes at least an upper track, a lower track, a shade assembly and an automatic winding means. The upper track has a holding trough to hold the automatic winding means and wire directing sets close to two sides thereof to direct a first lift cord and a second lift cord of the shade assembly. The automatic winding means has a retaining set to hinge a transmission assembly. The transmission assembly includes a first transmission wheel, a second transmission wheel and an elastic element. The elastic element is an S-shaped elastic reed with two ends coupling on the first and second transmission wheels. Through rotation of the automatic winding means, retraction and extension of the cordless window shade can be controlled to facilitate operation.

FIELD OF THE INVENTION

The present invention relates to a cordless window shade and particularly to a cordless window shade that has an automatic winding means to control retraction and extension of slats to facilitate operation.

BACKGROUND OF THE INVENTION

There are many different types of window shades on the market such as Venetian blinds, pleated window shades, roman shades and the like. They mainly aim to be installed at doors and windows of houses to block sunshine and serve decorative purpose. According to different user's requirements, the general window shade has a plurality of winding wheel sets to lift or lower the shade close to two sides thereof to control retraction and extension. The winding wheels are installed in a guiding trough of an upper track and wound around by multiple sets of lift cords. The lift cords are wound irregularly and easily entangled, hence are difficult to provide efficient control for retraction and extension of the shade.

SUMMARY OF THE INVENTION

The present invention aims to provide a cordless window shade to resolve the aforesaid problem of the conventional window shade that cannot be anchored at a selected elevation during retraction or extension, and also take into account of safety issue. Through rotation of an automatic winding means, the cordless window shade can be retracted and extended easily and smoothly.

To achieve the foregoing object, the cordless window shade of the invention mainly includes an upper track, a lower track, a shade assembly and an automatic winding means. The upper track has two sides coupling respectively with an anchor seat and a holding trough inside to hold the automatic winding means and a wire directing set located close to two sides thereof to direct a first lift cord and a second lift cord of the shade assembly. The automatic winding means has a retaining set pivotally coupled with a transmission assembly. The transmission assembly includes a first transmission wheel, a second transmission wheel and an elastic element. The elastic element is an S-shaped elastic reed with two ends coupling with the first transmission wheel and the second transmission wheel.

The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the invention.

FIG. 2 is an exploded view of the automatic winding means of the invention.

FIG. 3 is a perspective view of the automatic winding means of the invention.

FIG. 4 is a sectional view of a wire directing set and an upper track in a coupling condition.

FIG. 5 is a bottom view of a wire directing set.

FIG. 6 is a schematic view of the shade assembly of the invention pushed (or pulled) manually.

FIG. 7 is a schematic view of the automatic winding means and the first and second lift cords in a drawing condition.

FIG. 8 is an exploded view of another embodiment of the automatic winding means of the invention.

FIG. 9 is a top view of the automatic winding means and the first and second lift cord assemblies according to FIG. 8.

FIG. 10 is a perspective view of the automatic winding means and the first and second lift cord assemblies in a drawing condition according to FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1, 2 and 3, a cordless window shade 10 according to the invention includes an elongated upper track 20 with a holding trough 21 formed thereon, a lower track 30 spaced from the upper track 20 at a lower side, a shade assembly 40 bridging the upper track 20 and the lower track 30 and an automatic winding means 50 located in the holding trough 21 of the upper track 20.

The upper track 20 has two sides wedged respectively by an anchor seat 22 and 23 in the holding trough 21, and a guiding trough 241 at the bottom with latch sides 24 formed thereon corresponding to each other. The upper track 20 further has apertures running through the bottom thereof. In an embodiment shown in FIG. 1, at least one aperture such as a first aperture 25 and a second aperture 26 are formed on the upper track 20 to hold respectively a first wire directing set 27 and a second wire directing set 28 that contain respectively a first wire directing post 270 and a second wire directing post 280. The first and second wire directing sets 27 and 28 have respectively an extensible latch element 271 and 281 extended from the bottom thereof that have a first and a second threading holes 272 and 282 in the center (referring to FIGS. 4 and 5) to allow a first lift cord 421 and a second lift cord 422 to thread through and be directed and extended by the wire directing posts 270 and 280.

Refer to FIGS. 8 and 9 for another embodiment. There are a first, second, third and fourth apertures 251, 252, 261 and 262 mating wire directing sets 29 containing wire directing posts 291 and 292 of varying heights to facilitate latching of double lift cord assemblies 42 a at two sides of a large scale window shade 10 a on a retaining set 51 a which has a first transmission wheel 53 a containing double-layer first and second latch troughs 532 a and 5321 a that correspond to each other. An upper pressing board 511 is provided with multiple roller sets 5162 running through two sides thereof to be incorporated with winding of the wire directing posts 291 and 292 to reach a slat 41, so that the double lift cord assemblies 42 a do not entangle (referring to FIG. 10).

The lower track 30 is elongated and spaced from the upper track 20 at a lower side, and has a guiding trough 311 with corresponding latch sides 31 formed thereon and two coupling members 32 and 33 wedged at two sides.

The shade assembly 40 is located between the upper track 20 and the lower track 30, and includes the slat 41 and a lift cord assembly 42 containing the first lift cord 421 and second lift cord 422. Referring to the embodiment shown in the drawings, the slat 41 has two ends coupled respectively with a first wedged plate 411 and a second wedged plate 412 to be wedged in the guiding troughs 241 and 311 of the upper track 20 and lower track 30. The first lift cord 421 has one end 4211 fastened to the automatic winding means 50 through a first roller 516 at one side, and the other end 4212 winding the first wire directing set 27 and threading through the first aperture 25 of the upper track 20 to be fastened to the slat 41. The second lift cord 422 has one end 4221 fastened to the automatic winding means 50 through a second roller 5161 at another side and the other end 4222 winding the second wire directing set 28 and threading through the second aperture 26 to be fastened to the slat 41.

Referring to FIG. 2, the automatic winding means 50 is located in the holding trough 21 of the upper track 20, and has a retaining set 51 to hinge a transmission assembly 52. The transmission assembly 52 includes a first transmission wheel 53, a second transmission wheel 54 and an elastic element 55.

The retaining set 51 includes at least the upper pressing board 511, a lower pressing board 512 and a retaining element 513. The upper and lower pressing boards 511 and 512 are interposed by a first strut 514, a second strut 5141 and a third strut 5142 that have respectively a screw hole 515, 5151 and 5152 formed therein. The first roller 516 and second roller 5161 at two sides of the upper pressing board 511 are corresponding to and hinged on the first and third struts 514 and 5142, and are fastened through fastening elements 517 such as screws by running through the first and second rollers 516, and 5161 and engaging with the screw holes 515 and 5152.

The retaining element 513 is located above a central opening 510 of the upper pressing board 511 and has a padding sheet 5131 at the bottom with an opening 5132 formed thereon to be fastened to the upper side of the transmission assembly 52.

The transmission assembly 52 is located between the upper and lower pressing boards 511 and 512, and includes the first transmission wheel 53, second transmission wheel 54 and elastic element 55. The first transmission wheel 53 has a boss 531 at an upper side with a recess formed therein. The boss 531 has a first latch trough 532 and a second latch trough 5321 formed on corresponding sides and a through hole 533 formed thereon. The through hole 533 is coupled with the second strut 5141 located above the lower pressing board 512. The first transmission wheel 53 further has an indented annular portion 534 in the middle section. The second transmission wheel 54 has an opening 541 in the center to be coupled with the first strut 514 above the lower pressing board 512, and has another indented annular portion 542 in the middle section thereof. The elastic element 55 is an S-shaped elastic reed with two ends coupling with the indented annular portions 534 and 542 of the first and second transmission wheels 53 and 54.

When the cordless window shade 10 of the invention is in use, referring to FIGS. 6 and 7, the automatic winding means 50 is located in the holding trough 21 of the upper track 20, the first lift cord 421 has one end 4211 latched on the first latch trough 532 and the other end 4212 winding on the first roller 516 and threading through the first wire directing set 27 to be fastened to the slat 41. The one end 4221 of the second lift cord 422 is threaded and latched on the second latch trough 5321, and the other end 4222 is wound on the second roller 5161 and threaded through the second wire directing set 28 and fastened to the slat 41. Through rotation of the automatic winding means 50, retraction and extension of the cordless window shade 10 can be transmitted and controlled at the same time to make operation simpler and easier.

During retraction and extension of the shade assembly 40, referring to the drawings previously discussed and FIGS. 6 and 7, users can push (or pull) the lower track 30 with hands like a gravity balancing bar. By means of extension or retraction of the S-shaped elastic element 55 located between the first and second transmission wheels 53 and 54 of the automatic winding means 50, when to lift the shade assembly 40, the first and second lift cords 421 and 422 are wound on the first and second rollers 516 and 5161 through the first and second wire directing sets 27 and 28 to form a double winding on the periphery of the boss 531 in the counterclockwise direction to retract the slat 41. To lower the slat 41, loosen the first and second lift cords 421 and 422 in the clockwise direction, the slat 41 can be extended downwards. Meanwhile, the lower track 30 serves as the gravity balancing bar to prevent the lowered shade assembly 40 from being retracted and moved upwards. Thus operation of the cordless window shade 10 can be controlled effectively. 

1. A cordless window shade, comprising: an elongated upper track which has a first wire directing set and a second wire directing set at two sides; a lower track spaced from the upper track at a lower side; a shade assembly which is located between the upper track and the lower track and has a slat and a lift cord assembly; and an automatic winding means which is located in the upper track and coupled with the shade assembly and has a retaining set and a transmission assembly hinged inside.
 2. The cordless window shade of claim 1, wherein the automatic winding means includes an elastic element.
 3. The cordless window shade of claim 2, wherein the elastic element is an S-shaped elastic reed.
 4. The cordless window shade of claim 3, wherein the transmission assembly includes a first transmission wheel and a second transmission wheel, the elastic element having two ends coupling with the first transmission wheel and the second transmission wheel.
 5. The cordless window shade of claim 4, wherein the first transmission wheel has a boss on an upper side that has a first latch trough and a second latch trough corresponding to each other and an indented annular portion in a middle section thereof, the second transmission wheel having another indented annular portion corresponding to the first transmission wheel.
 6. The cordless window shade of claim 4, wherein the first transmission wheel has a first latch trough and a second latch trough that are formed on two layers corresponding to each other.
 7. The cordless window shade of claim 1, wherein the lift cord assembly coupling with the automatic winding means is a double-set lift cord assembly.
 8. The cordless window shade of claim 1, wherein the retaining set includes at least an upper pressing board, a lower pressing board and a retaining element.
 9. The cordless window shade of claim 8, wherein the upper pressing board and the lower pressing board are pivotally coupled with a first strut, a second strut and a third strut between them, the upper pressing board being hinged with a first roller and a second roller on two sides thereof corresponding to the first strut and the third strut.
 10. The cordless window shade of claim 9, wherein the first roller and the second roller consist of multiple roller sets.
 11. The cordless window shade of claim 1, wherein the upper track has a plurality of apertures running through the bottom thereof to latch the first wire directing set and the second wire directing set.
 12. The cordless window shade of claim 11, wherein the apertures are more than one.
 13. The cordless window shade of claim 11, wherein the first wire directing set and the second wire directing set have respectively an extensible latch element extended from the bottom thereof that have respectively a first threading hole and a second threading hole formed in the center.
 14. The cordless window shade of claim 11, wherein the first directing set and the second wire directing set have respectively a wire directing post of different heights. 